Multiplex bolting tool

ABSTRACT

A torque wrench for multiple bolts or nuts comprises multiple drive spindles that are arranged annularly around a center and are equipped or able to be equipped at the end with respective torque-applying tools, and a ratchet drive, associated with each drive spindle and driven by means of a hydraulic piston drive, for driving the drive spindles. In addition to the ratchet drive, a locking ratchet for locking the drive spindle acts on each drive spindle to keep it from turning back when exercising a return stroke movement of the drive ratchet. The locking ratchets are arranged in a locking bracket, which is penetrated by the drive spindles. The locking bracket has means for loosening the locking ratchets.

BACKGROUND

The present disclosure relates to a multiplex bolting tool, also calleda torque wrench for multiple bolts or nuts with multiple drive spindlesthat are arranged around a center and are equipped or able to beequipped at the end with respective torque-applying tools, and a ratchetdrive, associated with each drive spindle and driven by means of ahydraulic piston drive, for driving the drive spindles.

Torque wrenches for multiple bolts or nuts serve the purpose of applyingtorque to a plurality of screw connections in a single screwing processand thus, for example, tightening or loosening bolts, which are arrangedin a ring arrangement. Simultaneously applying torque to a plurality ofscrew connections shortens the time otherwise required for applyingtorque to several screw connections. Furthermore, when applying torqueto individual screw connections, which are arranged annularly around acenter, care must be taken to ensure that the components to be boltedtogether do not tilt relative to each other, which is why the screwconnections must be tightened according to a predefined screwingpattern. If this is not adhered to, there is a risk that a jointconsisting of multiple bolted connections will not be fastened properly.

Torque wrenches for multiple bolts or nuts are used for connectingrisers in oil or water wells, for example. At their ends, these pipeshave connecting flanges protruding outward in the radial direction. Toconnect two such pipes, the adjacent connecting flanges are boltedtogether with several screw connections. A torque wrench for multiplebolts or nuts suitable for this purpose is known from EP 2 288 476 B1.With this previously known torque wrench for multiple bolts or nuts, anumber of torque-applying devices corresponding to the number of screwsto be tightened or loosened is provided, for example six torquestations. The torque stations are arranged around a center. Thispreviously known torque-applying device is designed in an annular shapeand leaves a central opening through which the pipes with their flangescan be pulled. Each torque station is displaceable in the radialdirection, such that it can be adjusted from a non-operating position,in which a riser with its flange can be passed through a central openingof the torque wrench for multiple bolts or nuts, into an operatingposition for applying torque to the screw bolts. In order to applytorque to the screw connections of two adjacent connecting flanges ofsecond risers, the torque stations are displaced in the radial directionto their operating position. Each torque station has a drive spindle,which drives a socket as a torque-applying tool. The socket has an innercontour, which is complementary to the outer contour of the head of ascrew bolt that is meant to be tightened or loosened by means of thetorque station.

Each drive spindle is driven by its own hydraulically operated ratchetdrive. For this purpose, the piston rod of a hydraulically actuatedpiston is connected to the ratchet lever of the ratchet drive. Theratchet lever has a pawl, which drives a drive spindle that is rotatablysupported in the ratchet lever. The drive spindle has a square opening,into which the square drive, which has a complementary geometry to oneend of a socket as a torque-applying tool, can be inserted. The pawl isunder spring preload and interacts with the outer splines of the drivespindle under the spring preload. With a forward stroke of the pistonrod, the drive spindle is advanced by at least one tooth, proportionalto the executed stroke, relative to the pawl. With the return stroke,the ratchet lever is returned to its initial position, while the boltdoes not turn back. This alternation between the forward and returnstroke is carried out until the bolt is tightened with the intendedtorque.

Sometimes it is not possible to apply a sufficiently high torque to thescrew connection, specifically when, during the return stroke of aratchet lever following the execution of a forward stroke movement, forexample of a screw bolt, for moving the drive spindles, the drivespindle springs back due to the torsion introduced into the screw boltand also into the drive spindle. In that case, the pawl can no longer bemoved back by at least one tooth of the teeth of the drive spindle whenexecuting a return stroke movement acting on the ratchet lever. Althoughthe forward stroke and return stroke movement of the actuating cylinderis carried out correctly, a higher torque is not introduced into thescrew connection.

A single screw driving tool is known from U.S. Pat. No. 7,146,880 B1, inwhich, in addition to the ratchet drive, a safety ratchet acts on thedrive spindle. This safety ratchet blocks a springing back of the drivespindle as a consequence of torsion introduced in the same and/or thescrew connection, for example, in the screw bolt. However, such a deviceis not suitable to prevent a reverse-rotation of the drive spindles oftorque wrenches for multiple bolts or nuts, as the torque-applying toolsare bound with the respective bolts to be tightened, or their heads, dueto the reaction forces present while torque is applied, which means thatpulling the torque wrench for multiple bolts or nuts from the bolt headsis no longer possible.

SUMMARY

Proceeding from this background, an aspect of the present disclosure isto refine a torque wrench for multiple bolts or nuts with multiple drivespindles of the type mentioned above, which are arranged around acenter, such that it can be used to tighten screw connections with hightorques without having to accept a springing back of the drive spindles,wherein the torque wrench for multiple bolts or nuts can nevertheless bedetached easily from the tightened screw fasteners after torque has beenapplied.

According to the present disclosure, this aspect is provided by ageneric torque wrench for multiple bolts or nuts of the type mentionedat the onset, in which, in addition to the ratchet drive, a lockingratchet for locking the drive spindle acts on each drive spindle to keepit from turning back when performing a return stroke movement of thedrive ratchet, which locking ratchets are arranged in an annular lockingbracket penetrated by the drive spindles, and in which the lockingbracket has means for loosening the locking ratchets.

In this torque wrench for multiple bolts or nuts, a locking ratchet actson each drive spindle, in addition to the ratchet drive. The ratchet ofthe ratchet drive, as well as the locking ratchet, respectively act onthe drive spindle in the same direction. Both the pawl of the ratchetdrive and the locking pawl of the locking ratchet are in engagement withouter splines of the drive spindle. The pawl of the ratchet drive andthe locking pawl of the locking ratchet engage with the teeth of thedrive spindle in equal measure. This means that, when performing areturn stroke of the ratchet lever of the ratchet drive, the lockingratchet prevents the drive spindle from springing back, for example dueto a previously induced torsional force of the drive spindle. Thelocking ratchets of this torque wrench for multiple bolts or nuts arearranged in a locking bracket, which is penetrated by the drivespindles. The locking bracket thus follows the arrangement of the drivespindles arranged around a center. Typically, the locking bracket isannular. However, an embodiment in which it only extends across acircular segment also is possible. Even in such an embodiment, the drivespindles are arranged around a center, however, not in a ring structurebut only in a circular segment structure. Providing a locking bracket inwhich the locking ratchets are arranged makes it possible that saidlocking bracket has means for loosening the locking ratchets. With thesemeans, the locking pawls can be moved out of their position engagingwith outer splines of the drive spindle. For this purpose, the lockingpawls are typically held in the locking bracket translationally againstthe force of a return spring, against which spring force the lockingpawls are moved out of their locking position, in which their hooksengage with outer splines of the drive spindle. The guiding of a lockingpawl within the locking bracket typically is provided by the walls ofthe locking chamber inside which such a locking pawl is mounted. Such alocking chamber represents an expansion in the radial direction to adrive spindle opening.

In one example embodiment, each locking ratchet is associated with areturn lever by means of which the locking pawl can be moved out of theposition in which its teeth are engaged with those of the drive spindle.For this purpose, the locking pawl has at least one actuating area, withwhich such a return lever engages for moving the locking pawl out of theposition in which its teeth engage with those of the drive spindle. Inone embodiment, two actuating areas are provided, which are arranged onboth sides of a center part supporting the teeth of the locking pawl. Inone design of such an embodiment, the respective return levers engagewith a return lever accommodation of the locking bracket, which returnlever accommodation is arranged in the radial direction of the lockingbracket on the outer side with respect to the locking pawl. The otherend of the return lever protrudes beyond the locking bracket in theradial direction on the inner side and engages with a return leveraccommodation of an actuating element arranged in the radial directionon the inner side toward the locking bracket, which actuating elementcan be adjusted by a certain angular amount about the center of thearrangement of the drive spindles. In one embodiment, in which thelocking bracket is annular, the actuating element is also annular. Theactuating element is adjustable relative to the locking bracket aboutthe axis of the center of the arrangement of the drive spindles by atleast some angular degrees, wherein the range of adjustment issufficiently large, such that, when a rotational angle of the actuatingelement relative to the locking bracket is adjusted, the return leveraccommodation of said locking bracket and the end section of a returnlever engaging with said return lever accommodation can be displaced tosuch an extent that the locking pawl is moved out of its position inwhich it engages with the outer splines of the drive spindle because thereturn lever is supported on an actuating area of said locking pawl.Typically, the return lever is designed in an angle shape, wherein theoutside of the angle acts against the actuating area of the lockingpawl. If two actuating areas are provided on the locking pawl, tworeturn levers are used accordingly for moving the locking pawl.

An adjusting movement of the actuating element, which for example can bedesigned as an actuating ring, can be brought about by an actuating cam,which engages with a cam recess of the actuating ring. Such an actuatingcam is positioned transverse to the center axis of the arrangement ofthe drive spindles in a rotatable manner and typically is located on theend section of an actuating rod penetrating the locking bracket, whichactuating rod has a handle, for example a rotary knob, via which handlea rotating movement can be transferred onto the actuating rod, thusadjusting the actuating cam.

Before actuating the actuating rod for loosening the locking ratchets,the drive spindles are slightly tightened by means of the drive ratchetsin order to somewhat relieve the locking ratchets, which makes itpossible to then perform the loosening process by adjusting theactuating element.

In a compact design of the drive block of the torque wrench for multiplebolts or nuts, the locking ratchets, along with the locking bracket, aretypically arranged in a different plane than the ratchet drives withrespect to the longitudinal extension of the drive spindles. In oneversion of the torque wrench for multiple bolts or nuts, in which theratchet drives are arranged in two or multiple planes on top of eachother, nevertheless, the locking ratchets and the locking bracketsupporting said locking ratchets may be arranged on the same plane. Inone design of the torque wrench for multiple bolts or nuts, in which thelocking ratchets are arranged in a different plane than the ratchetdrives with respect to the longitudinal extension of the drive spindle,the drive spindle has outer splines extending into both planes or twoouter spline sections.

In a refinement of this torque wrench for multiple bolts or nuts asdescribed above, it is provided that the torque wrench for multiplebolts or nuts comprises an actuator unit for inducing a rotary movementin the drive spindles, having an actuating wheel mounted rotatably aboutthe axis of the center of the annular drive spindles as drive wheel,which drives respective output wheels fitted on the drive spindles,wherein the driving movement of the actuating wheel is transmitted tothe drive spindle via respective torque limiters.

This torque wrench for multiple bolts or nuts has an actuator unit,which is actuated before the actual tightening or loosening processbegins. The drive spindles can be moved with this actuator unit. Forthis purpose, the actuator unit has an actuating wheel, which is mountedrotatably about the axis of the center of the annular drive spindles.This actuating wheel is a drive wheel and drives respective outputwheels that are seated on the drive spindles. In this manner, a drivingmovement of the actuating wheel can be transferred to the drivespindles. A particular property of the actuator unit is that thetransfer of the driving movement of the actuator wheel to the drivespindles is performed by means of respective torque limiters. Thepurpose of these is to ensure that the screw connections to be tightenedcan be tightened with equal torque by means of the actuator unit on afirst pass. The actuating wheel can be operated manually, for examplewith a ratchet as a drive tool or with an electric screw tool. Ofcourse, it can also be operated hydraulically or pneumatically. Thetorque introduced into the actuating wheel is limited. Due to therotational movement of the actuator wheel and the resulting rotationalmovement of the drive spindles at the torque transmitted via the slipcouplings, the torque-applying tools seated on the drive ends of thedrive spindles are rotated. The torque-applying tools are typicallyspring-loaded torque-applying tools, which can be adjusted in thelongitudinal axial direction by a certain amount against the force of areturn spring on the drive spindle. If, when actuating the actuatordevice, the torque-applying tool for multiple bolts and nuts is heldagainst the fastening elements, for example, the bolts, thetorque-applying tools executed in this embodiment as sockets snap ontothe bolt heads when their respective, complementary contours are alignedwith each other. Thus, by operating the actuator unit with a low, inparticular manually transferred, torque, the torque-applying tools caneasily mate to the respective complementary contours of a fasteningelement and thus engage with them.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the present disclosure is described on the basis of anexample embodiment with reference to the attached drawings, wherein:

FIG. 1 shows a longitudinal-section view through a torque wrench formultiple bolts or nuts;

FIG. 2 shows a cross-section along line A-B of the torque wrench formultiple bolts or nuts of FIG. 1 ;

FIG. 3 shows another cross-section along the line C-D through the torquewrench for multiple bolts or nuts of FIG. 1 to represent a lockingdevice for locking the drive spindles in a locking position; and

FIG. 4 shows the representation of FIG. 3 with unlocked locking devices.

DETAILED DESCRIPTION

In the example embodiment shown in the drawings, a torque wrench formultiple bolts or nuts 1 is of a modular design and comprises a driveblock 2 as the first module, a locking unit 3 as the second module, andan actuator unit 4 as the third module. The individual modules 2, 3, 4are explained below. Even if, within the context of these explanations,these are combined for forming the torque wrench for multiple bolts ornuts 1, the individual modules 2, 3, 4 can also be used independently ofeach other together with differently designed components of a torquewrench for multiple bolts or nuts. For example, the functionalityachieved with the locking unit 3 can also be combined in connection withanother drive block or also without actuator unit or with a differentlyformed actuator unit. The same applies to the actuator unit 3.

The Drive Block

In the example embodiment shown here, eight drive spindles 5 areprovided in the drive block 2. These are arranged annularly around acenter. These are rotatably supported and held in the drive block 2. Thedrive block 2 has a cylindrical outer lateral surface. In the sectionalrepresentation of FIG. 1 , two drive spindles 5 are shown in a sectionalview, while three others, positioned behind them, are recognizable in afront view or partial view. The drive spindle 5 shown on the left inFIG. 1 and its drive are described in more detail in the following.These explanations also apply equally to the other drive spindles 5,which are designed in the same way as the drive spindle and its drivedescribed below.

In the example embodiment shown here, the drive block 2 is provided bytwo block discs 6, 6.1. The drive spindle 5 penetrates the block discs6, 6.1, which are connected to each other, and protrudes from them onboth ends. These sections of the drive spindle 5 protruding from thedrive block 2 are referenced as drive sections 7, 7.1 in the context ofthese explanations. As torque-applying tool, a socket 8 having an innercontour is seated on the drive section 7 in a torque-transferringmanner, which drive section 7 in FIG. 1 protrudes from the bottom of thedrive block 2. The socket 8 is detachably held on the drive section 7 ina manner known per se, specifically held by a locking ring 10pre-tensioned by a compression spring 9. If the locking ring 10 is movedin the direction of the drive block 2, the locking effect caused by aball not shown in the drawing is released, such that the socket 8 can bedetached from the drive section 7. The drive spindle 5 is supported inthe drive block 2 by bearings, which can also have seals at theiroutward-facing sides, which prevent an entry of contamination into thebearings of the drive spindle 5.

A ratchet drive serves for driving the drive spindle 5, as is describedmore clearly by means of the cross-sectional representation of FIG. 2 .In the example embodiment shown here, four ratchet drives are housed inthe upper block disc 6.1 and four further ratchet drives in the lowerblock disc 6. The respective ratchet drives for the individual drivespindles 5 are of the same design.

To provide a drive by means of such a ratchet drive, the drive spindle 5has circumferential, asymmetrical outer splines 11 in its drive section,as is typical for ratchet drives. The longer spline flanks point in thedrive direction of the drive spindle 5. The shorter spline flanks pointin the opposite rotational direction. The ratchet drive comprises apiston-cylinder arrangement 12, the piston rod 13 of which acts on aratchet lever 14. A piston 13.1 supporting the piston rod 13 is locatedin a cylinder housing provided by a screw-in cylinder 15. The cylinderhousing 15 has two fluid connectors, of which a fluid connector 16 isvisible in the sectional view of FIG. 2 . This fluid connector 16 opensinto the bottom area of a hole drilled in the drive block 2, whichreceives the screw-in cylinder 15. Hydraulic fluid is fed into thecylinder housing 15 via the fluid connector 16 for moving the piston13.1 with its piston rod 13 to perform a forward stroke. The hydraulicconnector for the return stroke opens radially into the screw-incylinder 15 at the side of the piston 13.1 opposite to the fluidconnector 16. The piston rod 13 is connected to the ratchet lever 14 ina manner transferring both compressive and tensile forces, such that aforward stroke performed by the piston leads to a forward strokemovement by the ratchet lever 14. By performing a return stroke, theratchet lever 14 is returned to its position shown in FIG. 2 . Thepiston 13.1 is connected to the ratchet lever 14 via a push rod as anextension of the piston rod 13. This push rod penetrates a hole in theratchet lever 14, which extends in the direction of movement of thepiston rod 13. Between the push rod and the piston rod 13 is anactuating tappet with which the piston rod 13 interacts for transferringa forward stroke movement against a bolt of the ratchet lever 14providing the aforementioned hole that is penetrated by the push rod.The push rod penetrates the hole. A retaining disc, for example a snapring, is located on the section of the push rod protruding from thehole, by means of which disc the ratchet lever 14 is moved along whenthe piston rod 13 performs a return stroke movement.

A pawl 17 is inserted in the ratchet lever 14. The teeth of the pawl 17,which is under spring preload (not shown in the drawing), engage withthe outer splines 11 of the drive spindle 5. The teeth of the pawl 17are designed to be complementary to the outer splines 11 of the drivespindle 5. During a forward stroke of the piston rod 13, which leads toa rotation to the right of the ratchet lever 14, the drive spindle 5 ismoved clockwise. In the example embodiment shown here, the drive spindleis moved by one tooth when a forward stroke is performed. During areturn stroke, the ratchet lever 14, along with the pawl 17, is returnedin its position shown in FIG. 2 , while the drive spindle 5 remains inits position into which it had been moved by the previously performeddrive movement.

The drive block 2 shown in FIG. 1 shows the stacked arrangement of theratchet drives offset at an angle in the two block discs 6, 6.1. Thedrive block 2 of the torque wrench for multiple bolts or nuts 1 has afirst hydraulic fluid connector for feeding hydraulic fluid from ahydraulic pump for performing the forward stroke and a second hydraulicconnector for feeding hydraulic fluid for performing the return stroke.These hydraulic connectors are not visible in the drawing. The hydraulicfluid connector for the forward stroke is connected to a fluiddistribution cavity designed as an annular duct 18 by means of a ductextending in the radial direction. The annular duct 18 is located in thewall of a central hole located in the drive block 2. The hole is filledwith a cylindrical fluid distributor 19. This distributor is crossed bytransverse bores 20 at the height of the annular duct 18. On both sidesof the annular duct 18, sealing rings are provided in slots for sealingthe lateral surface of the fluid distributor 19. The annular duct 18serves for supplying hydraulic fluid required for the forward stroke ofthe piston-cylinder arrangements 12 of the ratchet drives arranged inthe block disc 6.1. Fluid ducts also open into the annular duct 18,which fluid ducts establish a connection between the annular duct 18 andthe piston-cylinder arrangements 12 installed in the block disc 6.1 forthe forward stroke. A small section 21 of such a line is visible in FIG.2 , as it is inclined relative to a horizontal plane. The transversebore 22, which is adjacent to the section 21, is used to establish afluid connection between the radial extension of the section 21 and thefluid connector 16 or the cylinder housing 15. This transverse bore 22is closed at its end that is opposite to the screw-in cylinder 15. Theaforementioned transverse bores 20 serve to also supply thepiston-cylinder arrangement of the block disc 6 with hydraulic fluid forthe forward stroke. Said bores open into a central fluid duct 23,through which a fluid path is established to the same plane as a secondannular chamber 24 in the lower block disc 6. Four fluid ducts also openinto the annular chamber 24 for establishing a fluid connection betweena first fluid connector of the cylinder housings received in the blockdisc 6.

The piston-cylinder arrangements 12 of the drive block 2 are alldesigned identically. Therefore, the same amount of hydraulic fluid isrequired for performing a forward stroke of each piston-cylinderarrangement.

The hydraulic fluid connection for feeding hydraulic fluid for thereturn stroke opens into an annular fluid distributor 25 connected tothe top of the block disc 6.1. The fluid distributor 25 provides anotherannular duct 26, into which fluid ducts (not shown in detail in thedrawing) open, which fluid ducts are connected to respective backstrokefluid connectors of a screw-in cylinder 15 at their other end. While thefluid ducts for feeding hydraulic fluid to the piston-cylinderarrangements 12 largely extend in the radial direction, the fluid ductsfor feeding the hydraulic fluid for performing a return stroke largelyextend in the vertical direction and thus in the direction of thelongitudinal extension of the drive spindles 5.

In the example embodiment shown here, the annular duct 26 is provided bytwo annular bodies 27, 28 arranged concentrically to each other. Thegeometry of the annular duct 26 is located in the inner wall of theannular body 27 located on the outer side as seen in the radialdirection. The inner side of the annular duct 26, as seen in the radialdirection, is closed by the outer lateral surface of the second annularbody 28. Ring seals arranged adjacent to the annular duct 26 ensure thenecessary tightness. The annular body 28 is penetrated by the drivespindles 5, as is visible in FIGS. 1 and 3 .

The Locking Unit

In the example embodiment shown here, the inner annular body 28 at thesame time represents a locking bracket. The drive spindles 5 penetratethe annular locking bracket 28. The locking bracket 28 bears respectivelocking ratchets 29 associated with each drive spindle 5 for locking therespective drive spindle 5 against turning back or springing back whenthe drive ratchet performs a return stroke movement, i.e., when the pawlwith its teeth is moved away from the outer splines 11 of the drivespindle 5. Each locking ratchet 29 comprises a locking chamber 30 as anextension of the opening 31, which is penetrated by the drive spindle 5.A locking pawl 32 is located in the locking chamber 30, the teeth ofwhich locking pawl 32 under spring-load (not shown in the drawings)engage with the outer splines 33, which also are present at this sectionof the drive spindle 5. The outer splines 33 and the outer splines 11 ofthe drive spindle 5 are asymmetrical with the same orientation and aredesigned with the same number of teeth. The same applies to theoperational direction of the locking pawl 30 and the pawl 17. Thelocking ratchet 29 has the effect that the locking ratchet 29 remains inits locking position when a return stroke of the drive ratchet isperformed. This makes possible an application of torque to the drivespindle 5 and thus to the torque-applying tool, designed as a socket 8in the example embodiment shown here, and to a bolt to be tightened insuch a measure that torsional force is exerted onto the bolt and/or thedrive spindle 5. Due to the blocking effect of the locking ratchet 29,an otherwise unavoidable springing back of the torsion introduced intothe drive spindle 5 and/or the bolt is effectively prevented when areturn stroke is performed.

The locking pawl 32 is designed T-shaped in its cross section, whereinthe middle portion bears the locking teeth interacting with the outersplines 33 of the drive spindle 5. The sections adjacent to both sideseach have an actuating area with which an actuating lever 34 makescontact. The actuating lever 34 serves the purpose of moving the lockingpawl 29 out of the position in which its teeth engage with the outersplines 33 of the drive spindle 5, when it is to be unlocked. Theactuating lever 34 is held with its radially outward end in a returnlever accommodation 35 of the locking bracket 28. Although the lockinglever 34 is designed as an angle, as shown in FIG. 3 , it penetrates thelocking bracket 28 in an essentially radial direction and with anactuating section 36 protrudes from the locking bracket 28 toward theinside, as seen in the radial direction. The actuating lever 34 isrouted in an actuating lever channel 37 of the locking bracket 28. Thelocking channel 37 has sufficient clearance in the circumferentialdirection of the locking bracket 28 to allow a movement of the actuatinglever 34 to move the locking pawl 29 away from the drive spindle 5,specifically move it far enough away that the engagement of teeth of thelocking pawl 29 with the outer splines 33 of the drive spindle 5, whichotherwise is effected by the spring load, can be released. Furtherinward, as seen in the radial direction, from the locking bracket 28 isan actuating ring 38, which in turn has a return lever accommodation 39for the actuating section 36 of the actuating lever 34. The actuatingring 38 can be rotationally displaced relative to the locking bracket28, as indicated by an arrow in FIG. 3 . An actuating rod 40 serves fordisplacing the actuating ring 28, which rod bears an actuating cam 41 atits end portion engaging with the actuating ring 38. The actuating rod40 is routed outward through the locking bracket 28, the outer annularbody 27 and through a housing 42, and bears a handle 43 at its endprotruding from the outer housing 42, via which handle 43 the actuatingrod 40 can be rotated for displacing the actuating ring 38. FIG. 3 showsthe locking bracket 28 with its locking ratchets 29 and the actuatingring 38 in the tightening position of the torque wrench for multiplebolts or nuts 1, in which position the locking ratchets 29 engage withthe outer splines 33 of the drive spindle 5 in a manner that locks thelatter.

To push back the locking pawls 30 from their position in which theyengage with the outer splines 31 of the drive spindles 5, the actuatingrod 40 is rotated by means of the handle by about 180 degrees. Due tothe engagement of the eccentrically designed actuating cam 41 with anactuating cam recess 44 of the actuating ring 38, the actuating ring 38is adjusted counterclockwise, whereby the actuating levers 34 fittedagainst the actuating areas move the locking pawls 32 away from therespective drive spindle 5. If a torsional force acts on the lockingpawls 32 via the drive spindles 5 and it is not easily possible torelease the locking mechanism by turning the actuating rod 40, aspreviously described, the piston cylinder arrangements 12 are controlledto perform a forward stroke, such that the torsional force acting on thelocking pawls 32 is reduced. The torque wrench for multiple bolts ornuts 1 can then easily be removed from the tightened bolts.

The locking unit 3 thus makes it possible to tighten screw connectionswith a particularly high torque using the torque wrench for multiplebolts or nuts 1, in particular with such a torque at which the screwconnection remains tight even when exposed to a certain torsion of thecomponents that were fastened together.

The Actuator Unit

The actuator unit 4 acts on the drive sections 7.1 of the drive spindles5 opposite to the torque-applying tools (see FIG. 1 ). The actuator unit4 serves for inducing a rotational movement in the drive spindles 5, inorder to bring the inner contour of the sockets 8 seated on the drivesections 7 into alignment with the outer contour of the individualbolts. In addition, the actuator unit 4 serves the purpose of bringingthe bolts to be tightened by means of the torque wrench for multiplebolts or nuts 1 to a uniform preload before the hydraulic tighteningprocess.

The actuator unit 4 comprises a central actuating wheel 45 with a drivecontour 46 located centrically within said wheel, into which contour,for example, the square shaft of a ratchet or another manual orelectrical tool can be inserted. By turning the actuating wheel 45, thedrive spindles 5 can be driven via respective torque limiters. Theactuating wheel 45 bears outer splines 47, which mesh with an outputwheel 48 that is seated on the drive section 7.1. The output wheel 48has corresponding, complementary teeth 49 and acts on two coupling rings50, 50.1 with its radial inner side having two coupling surfaces. Theinside of the output wheel 48 is conically tapered for this purpose andacts against complementary inclined coupling surfaces of the couplingrings 50, 51. The upper coupling ring 50 in FIG. 1 acts in the directionof the longitudinal axis of the drive spindle 5 against a counterbearing plate 51. The lower coupling ring 50.1 is under the preload of acompression spring 52 acting on it, which spring is supported on acounter bearing with its other end; through this compression spring 52,the coupling ring 50.1, via the output wheel 48, acts in the directionof the other coupling ring 50. Thus, the force transfer from the outputwheel 48 to the coupling rings 50, 50.1 seated on the drive section 7.1of the drive spindle 5 in a torque-transferring manner is limited by thecompression spring 52.

As the actuating wheel 45 drives all drive spindles 5 in the samemanner, a low torque suffices to bring the torque-applying tools seatedon the opposite drive section 7 of the drive spindles 5 into theposition required for engagement with, for example, the head of a bolt.In addition, the bolts are tightened at the same preload by the drivevia the actuating wheel 45. If a screw bolt is tightened with a certainpreload, the slip coupling installed on the respective drive spindle 7.1operates as a torque limiter, such that this drive spindle 5 is notturned further by additional rotary movements of the actuating wheel 45,wherein, on the other hand, the other drive spindles, which can stilltransfer the torque transferred via the torque limiter, are turnedfurther, specifically until their respective torque limiters formed bythe coupling discs 50, 50.1 also are triggered. Thus, a uniform torquelimitation of the torque transferred via the actuating wheel 45 to thedrive spindles 5 is achieved in a simple manner

Other Operational Devices

The torque wrench for multiple bolts or nuts 1 is associated with ahydraulic unit and a control device for controlling the hydraulic unitfor its operation. The hydraulic unit comprises a hydraulic pump, afluid tank for the storage of hydraulic fluid, typically hydraulic oil,as well as a fluid pressure output for the forward stroke and anotherfluid pressure output for the return stroke. In addition, the hydraulicunit has a flow measurement device for detecting the hydraulic fluidquantity conveyed, which is used to detect said quantity during theoperation of the hydraulic unit. According to a preferred operatingmethod of the torque wrench for multiple bolts or nuts, the hydraulicunit is controlled dependent on fluid flow rates, based on informationfrom its flow measurement device. This ensures that a switch from aforward stroke to a return stroke of the hydraulic actuator cylinders ofthe torque wrench for multiple bolts or nuts takes place only when thepredefined hydraulic fluid quantity has been conveyed. This predefinedhydraulic fluid flow quantity corresponds to the hydraulic fluid volumerequired to move the piston arranged in each hydraulic actuatingcylinder from its one end position to its other end position. Thisensures that a switch from a forward stroke movement to a return strokemovement takes place only when all pistons of the ratchet drives haveactually been moved in equal measures. The same applies to a switch froma return stroke movement to a forward stroke movement. When thehydraulic unit is controlled in this manner, it is therefore irrelevantwhether the desired stroke is carried out synchronously in all actuatorcylinders or with a small time offset. In order to be able to determinethe respective quantity of hydraulic fluid, the torque wrench formultiple bolts or nuts is actuated several times to perform of a strokebefore it is used to actually tighten or loosen a bolt. The respectivefluid volume conveyed is recorded therein. By repeating this processmultiple times, a reliable reference value for the fluid volume conveyedis obtained. This fluid quantity conveyed then determines the switchingtime. If in such an operation of the hydraulic unit of the torque wrenchfor multiple bolts or nuts the hydraulic fluid flow quantity requiredfor switching from a forward stroke movement to a return stroke movementcould no longer be conveyed, because at least one of the screwconnections to be tightened is already sufficiently tightened, causingthe actuator cylinder not to be moved further by means of the appliedhydraulic pressure, the hydraulic unit typically switches off. If nomore hydraulic fluid is conveyed, all screw connections are tightenedwith the same torque, as the hydraulic oil pressure remains constant. Inthis mode of operation, the force with which the screw connections aretightened is dependent on the pressure with which the hydraulic fluid isconveyed. With such a torque wrench for multiple bolts or nuts, screwconnections can also be tightened with very high torques.

The operation of the hydraulic unit and thus of the torque wrench formultiple bolts or nuts can also be carried out at different pressurelevels. It is possible to perform a first tightening step with only alow hydraulic pressure (a few bar). This step of tightening the boltsmerely serves for the torque-applying tools to mate their contour to thecomplementary fastening elements to be driven, for example the head of abolt, and in that all screw connections are brought into a same initialstate with respect to their fastening position. Once this is achieved,the actual tightening of the screw connections takes place. For thispurpose, the hydraulic pressure of the hydraulic unit is raised to thepressure corresponding to the torque to be applied. Herein, it isentirely possible to apply pressures from 600 to 800 bar. Of course, itis also possible to provide higher pressures. The tightening process iscarried out by means of the fluid control process dependent on fluidquantities conveyed, as already described above.

List of reference numbers  1 Torque wrench  2 Drive block  3 Lockingunit  4 Actuator unit  5 Drive spindle  6, 6.1 Block disc  7, 7.1 Drivesection  8 Socket  9 Compression spring 10 Locking ring 11 Outer splines12 Piston-cylinder arrangement 13 Piston rod 13.1 Piston 14 Ratchetlever 15 Cylinder housing 16 Fluid connector 17 Pawl 18 Annular duct 19Fluid distributor 20 Transverse bore 21 Section 22 Transverse bore 23Fluid duct 24 Annular chamber 25 Fluid distributor 26 Annular duct 27Ring body 28 Annular body/locking bracket 29 Locking ratchet 30 Lockingchamber 31 Opening 32 Locking pawl 33 Outer splines 34 Actuating lever35 Return lever accommodation 36 Actuating section 37 Actuating leverchannel 38 Actuating ring 39 Return lever accommodation 40 Actuating rod41 Actuating cam 42 Housing 43 Handle 44 Actuating cam recess 45Actuating wheel 46 Drive contour 47 Outer splines 48 Output wheel 49Teeth 50, 50.1 Coupling ring 51 Counter bearing disc 52 Compressionspring

The invention claimed is:
 1. A multiplex bolting tool for multiple boltsor nuts with multiple drive spindles that are arranged around a centerand are equipped or able to be equipped at an end with respectivetorque-applying tools, and a ratchet drive, associated with each drivespindle and driven by means of a hydraulic piston drive, for driving thedrive spindles, comprising: locking ratchets for locking the drivespindles, each locking ratchet acts on one of the drive spindles, inaddition to the ratchet drive, to keep the drive spindle from turningback when the ratchet drive performs a return stroke movement, whereinthe locking ratchets are arranged in a locking bracket penetrated by thedrive spindles, and the locking bracket has means for loosening thelocking ratchets.
 2. The multiplex bolting tool of claim 1, wherein eachdrive spindle opening of the locking bracket comprises a locking chamberin which a locking pawl acting on the drive spindle under spring load isreceived.
 3. The multiplex bolting tool of claim 2, wherein the lockingpawl has at least one actuating area facing the drive spindle, againstwhich actuating area a return lever is fitted for moving the lockingpawl away from a position in which the locking pawl locks the drivespindle.
 4. The multiplex bolting tool of claim 3, wherein the lockingpawl has two actuating areas which enclose a middle part supportingteeth of the locking pawl.
 5. The multiplex bolting tool of claim 3,wherein each return lever associated with the locking ratchets protrudeswith one end into a return lever accommodation of the locking bracketand with its other end protrudes from the locking bracket in the radialdirection and engages with a return lever accommodation of an actuatingring which is concentrically rotatable to the locking bracket fordisplacing the return levers.
 6. The multiplex bolting tool of claim 5,wherein the actuating ring is arranged on an inner side of the lockingbracket, as seen in the radial direction, and has an actuating camrecess in which an actuating cam is held rotatably relative to thelocking bracket for adjusting the actuating ring.
 7. The multiplexbolting tool of claim 6, wherein the actuating cam is provided on anactuating rod, which extends in the radial direction and penetrates thelocking bracket, with an end of the actuating rod protruding from thelocking bracket in the radial direction having a handle.
 8. Themultiplex bolting tool of claim 5, wherein the return lever has an edgepointing to an actuating area of the locking pawl, starting from which afirst bar of the return lever extends to the return lever accommodationof the locking bracket and a second bar of the return lever extends intothe return lever accommodation of the actuating ring.
 9. The multiplexbolting tool of claim 1, further comprising: a drive block in which thedrive spindles are rotatably supported and held, each drive spindlehaving a drive section protruding from the drive block on each end,wherein the drive sections of the drive spindles serve to bear thetorque-applying tools on one side of the drive block, wherein, in thedrive block, pistons of the piston drives are routed in cylinderhousings such that said pistons are translationally displaceable in bothdirections, wherein piston rods of the pistons are each kinematicallyconnected to a ratchet lever for transferring a forward stroke movementand a return stroke movement to the respective ratchet levers withpawls, and wherein the drive block has at least one first fluiddistribution cavity in a center area thereof, into which multiple fluidducts located in the drive block open, said multiple fluid ducts eachestablish a fluid connection between the at least one first fluiddistribution cavity and a first fluid input of one of the cylinderhousings, and wherein, on a flat side of the drive block, a fluiddistributor with an annular duct connected to a fluid supply duct isarranged as a second fluid distribution cavity, into which multiplefluid ducts open, said multiple fluid ducts each establish a fluidconnection between the second fluid distribution cavity and a secondfluid input of one of the cylinder housings.
 10. The multiplex boltingtool of claim 9, wherein the at least one first fluid distributioncavity located in the center area of the drive block is designed as anannular duct.
 11. The multiplex bolting tool of claim 9, wherein thedrive block is composed of at least two block discs, wherein multipleratchet drives are arranged in each block disc.
 12. The multiplexbolting tool of claim 11, wherein the at least one first fluiddistribution cavity comprises two first fluid distribution cavities,with a first fluid distribution cavity associated with each of the blockdiscs, and fluid connections are established between the two first fluiddistribution cavities by another fluid distributor.
 13. The multiplexbolting tool of claim 9, wherein the drive spindles bear spring-loadedsockets as the torque-applying tools.
 14. The multiplex bolting tool ofclaim 9, wherein the direction of movement of each piston rod of theratchet drives is the same as the direction of movement of therespective ratchet lever driven thereby, and the ratchet lever isdirectly driven by the piston rod.
 15. The multiplex bolting tool ofclaim 9, wherein the direction of movement of each piston rod of theratchet drives extends at an angle to the direction of movement of therespective ratchet lever driven thereby, and in order to transfer theforward stroke movement and the return stroke movement of the piston rodto the respective ratchet lever, a link is arranged between the pistonrod and the ratchet lever such that one end of the link is articulatedto the piston rod and the other end of the link is articulated to theratchet lever.
 16. The multiplex bolting tool of claim 15, wherein thelink is a lever of a two-bar toggle joint.
 17. The multiplex boltingtool of claim 9, wherein the multiplex bolting tool is associated with ahydraulic unit comprising a hydraulic pump, a fluid tank, a fluidpressure output for the forward stroke and a further fluid pressureoutput for the return stroke, and at least one flow measurement deviceas well as a control unit for controlling the hydraulic unit, by whichcontrol device the hydraulic unit, during operation of the multiplexbolting tool, is switched between a forward stroke conveyance and areturn stroke conveyance dependent on a fluid quantity conveyed.
 18. Themultiplex bolting tool of claim 1, further comprising an actuator unitfor inducing a rotary movement in the drive spindles, the actuator unithaving an actuating wheel mounted rotatably about the axis of the centerof the annular arrangement of the drive spindles as drive wheel, whichdrives respective output wheels fitted on the drive spindles, whereindriving movement of the actuating wheel is transmitted to the drivespindles via respective torque limiters.
 19. The multiplex bolting toolof claim 18, wherein the output wheels are connected to the drivespindles via a slip coupling for transferring drive force to the drivespindles in a torque-limited manner, and respective gear rings of theoutput wheels mesh with outer splines of the actuating wheel.
 20. Themultiplex bolting tool of claim 19, wherein the slip coupling of eachdrive spindle comprises two coupling discs seated on said drive spindlein a torque-transferring manner, each having a coupling surface inclinedrelative to the longitudinal extension of the drive spindle, whichcoupling surfaces are inclined to each other for forming an output wheelaccommodation, and also comprises the output wheel, which engages withthe output wheel accommodation with its inner side designedcomplementary to the coupling surfaces and which fits against thecoupling surfaces of the coupling discs under preload.
 21. The multiplexbolting tool of claim 20, wherein the coupling surfaces are curved inthe direction of their inclination.
 22. The multiplex bolting tool ofclaim 20, wherein the preload of the slip coupling is provided by acompression spring acting on one of the coupling discs.
 23. Themultiplex bolting tool of claim 20, wherein the preload of the slipcoupling is adjustable.
 24. The multiplex bolting tool of claim 18,wherein the actuating wheel has a drive contour for connecting a drivetool.
 25. The multiplex bolting tool of claim 18, further comprising adrive block, wherein the actuator unit is designed such that it can bedetachably connected to the drive block and components of the actuatorunit are received in a housing with an upper part and a lower part.